Display screen or portion thereof with a graphical user interface



The FIGURE is a front elevation view of a display screen or portionthereof with a graphical user interface showing our new design.

The broken lines shown in the FIGURE illustrate the display screen andportions of the graphical user interface that form no part of theclaimed design.

CLAIM The ornamental design for a display screen or portion thereof witha graphical user interface, as shown and described.